Regression Analysis By Example -

(Error): The "noise"—factors you didn't measure (like a local parade or a broken espresso machine). 2. Checking the "Goodness of Fit"

Is the relationship real or just a fluke? A p-value under 0.05 generally means your result is statistically significant. 3. Adding Complexity (Multiple Regression) Temperature isn't the only factor. You might add: X2cap X sub 2 : Is it a weekend? (0 for no, 1 for yes). X3cap X sub 3 : Is there a discount running?Now your model looks like: 4. The "Golden Rules" (Assumptions) Regression Analysis by Example

): This tells you what percentage of the "story" is explained by temperature. If , then 85% of your sales fluctuations are due to heat. (Error): The "noise"—factors you didn't measure (like a